The purpose of this project is to apply recombinant DNA technology to the analysis of the mouse Beta-major-globin 5 feet flanking DNA sequences. Various plasmids have been constructed which will allow the study of the effect of DNA enchancing sequences on activity of the Beta-globin promoter, both in tissue culture cells and in whole mice. These are called expression vectors. We hope to be able to identify DNA regions required for maximal induction of Beta-globin synthesis using these plasmids in cultured erythroid cells and in intact mice.